This year I decided to try growing potatoes again. I've not had great luck in the past, for a number of reasons. Improper soil and planting technique, too little sun, etc. were all to blame. This year I planted small variety red and buttercream potatoes in two types of containers to see if there was a way to succeed. One was a buttercream and the other was a red French Fingerling, both Cinacia brand and purchased in the produce section of Whole Foods.
The other day I showed what I was able to grow in a #15 size nursery pot on the deck, and today I harvested the tower of potatoes I grew in a landscape fabric cylinder containing potting soil, and supported by a heavy wire cage. The tower took about 8 cubic feet of potting soil, and when the potatoes quit growing they were as tall as I am. The dirt in the 2' diameter "container" was about 3' high.
First I knocked the cage over and opened it up so I could get at the landscape fabric bag inside easily. I didn't want to damage my crop using a shovel or pitchfork, so I just rolled the bag around on the ground to loosen the plants and discover the tubers.
I had high hopes this one would yield a ton of potatoes, but I was wrong. The soil was great, slightly moist in spots, but overall quite dry, which may have been part of the problem. Or maybe the potato variety itself wasn't a high yielder. Or maybe both. In any event, I got proportionally more potatoes (by far) from the plastic container on the deck. Maybe it just got watered more frequently because it was more accessible to me and the hose.
My Golden Gate Gardening book suggests that we can plant three crops each year in this area, and I'm definitely going to try another one this month.
Here's a helpful "how to" site for growing potatoes in containers.